Mold closing device for an injection molding machine

ABSTRACT

A mold closing device of an injection molding machine for producing plastic parts made of two or more plastic components includes a central mold carrier element which is arranged between two outer mold mounting plates and has two or four opposing mold mounting areas arranged in pairs for affixing two or four mold halves and which is fitted with a turning device supported in a supporting frame. Each of the mold halves of the mold carrier element can be closed against the mold halves of the outer mold mounting plates by a drive mechanism and a mold pressure unit. The outer mold mounting plates are interconnected by columns which extend through the supporting frame for the central mold carrier element. The supporting frame is fixedly connected to the machine frame while the outer mold mounting plate is displaceably supported on the machine frame.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a division of prior filed copending U.S. applicationSer. No. 10/770,124, filed application Feb. 2, 2004, which is acontinuation of prior filed copending PCT International application no.PCT/EP02/07985, filed Jul. 18, 2002, which designated the United Statesand on which priority is claimed under 35 U.S.C. §120, and which claimsthe priority of German Patent Application, Serial No. 101 38 087.9,filed Aug. 3, 2001, pursuant to 35 U.S.C. 119(a)-(d), the contents ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a mold closing device for an injectionmolding machine, and more particularly to a mold closing device forproducing large high-precision multi-component plastic parts.

Mold closing devices are known in the art. For example, British Pat. No.GB 2 300 142 describes a mold closing device, wherein each of the twoouter mold mounting plates is made of one mold mounting plate that isfixedly secured to the machine frame and another mold mounting platethat is movably supported on the machine frame. The center mold carrierelement is also movably supported on the machine frame by way of asupporting frame. Because the center mold carrier element which isrotatably arranged in the supporting frame is moveable, this componentis relatively unstable, so that typically only lightweight mold halvescan be placed on the mold mounting areas of the rotatable mold carrierelement. Since the center mold carrier element and the moveable outermold mounting plate represent two successively arranged moveable moldcarrying units, the large tolerances render the mold closing unit veryinaccurate, whereby the parallelism between the plates and thestationery outer mold mounting plate which is stationary in the machineframe is difficult to maintain.

Another type of mold closing device is known from German patentpublication no. DE 197 33 667, which includes a stationary and amoveable mold mounting plate and a mold half carrier which is supportedin support blocks that are moveable relative to the moveable mountingplate and rotatable about a vertical axis. The moveable mold mountingplate and the mold half carrier can be moved towards the stationery moldmounting plate so as to provide a closing pressure when a thermoplasticplastic is injected. This device disadvantageously also suffers from therelative instability of the device due to the large tolerances, asdescribed above with reference to British patent publication no. GB 2300 142.

German Pat. No. DE 36 20 175 describes an injection molding machine withat least two plasticizing and injection units as well as a stationarymold mounting plate and a moveable mold mounting plate that is guided bystationary tie bars. Each of stationary tie bars carries one set of themold halves of injection molding molds. A prismatic core carrying bodyis arranged between the stationary tie bars which can rotate about itsaxis and is displaceable in the direction of the stationery tie bars.The axis-parallel side faces of the core carrying body include the otherset of mold halves of the injection molding molds. This core carryingbody is actually not supported on the machine bed, but is held only bytie bars that are movably supported on the moveable mold mounting plate.In other words, only the core carrying bodies and the associated moldhalves which are lightweight are operational. This particular supportstructure of the core carrying body relative to the moveable moldmounting plate, which is not supported on either the machine bed or thetie bars used for the closing motion, causes the device to beparticularly unstable and hence has all the disadvantages describedabove with reference to British patent publication no. GB 2 300 142.

A tie bar pulling device for a 2-platen or 3-platen injection moldingmachine is described in German patent publication no. DE 197 10 412,wherein the tie bars extend through two mold mounting plates which eachcarries a corresponding mold half. When the mold is opened, the tie barsare pulled out of one mounting plate with which they are interlocked inthe closed state, allowing access to the space between the mold mountingplates. This device, unlike the present invention, is directed to aninjection molding machine without a turning device for the mold, whichmakes it difficult to produce multi-component injection molded parts.

German Pat. No. DE 196 50 854 describes a method and a device forproducing multilayer plastic parts, whereby a plastic injection moldedpart is coated with at least one layer of 2-component Thermosettingplastics and the two components are injection-molded successively in asynchronous cycle in the same mold. For this purpose, a baseplate isused which supports two mold halves that are arranged side-by-side androtatably supported for rotation about a horizontal longitudinal machineaxis. Female molds of an injection molding machine and a RIM device arearranged opposite to the mold halves. After injecting thermoplasticmaterial with the injection molding machine, the baseplate is rotated by180°. In the following cycle, a new thermoplastic part is molded whilethe part produced in the preceding cycle is coated with the 2-componentThermosetting plastics. With this device, both injection molding devicesare disadvantageously located on the same side of the machine, whichposes significant problems at the installation side and for theoperation of the injection molding devices. Moreover, this device issuitable only for producing small plastic parts, since the two moldhalves could otherwise not be arranged side-by-side. It is not clearfrom the description how a baseplate that is rotatable about thelongitudinal mold axis can be fixedly connected with the female molds ofthe injection molding machine and the RIM device, which leavesunanswered the question concerning the accuracy of the mold fit and theavailability of a sufficiently high closing pressure.

It would therefore be desirable and advantageous to provide a moldclosing device with an improved stability, which obviates prior artshortcomings and is able to specifically produce large high-precisionmulti-component plastic parts.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a mold closing device forproducing a plastic part made of two or more plastic components includestwo outer mold mounting plates supporting mold halves, a center moldcarrier element rotatably arranged between the two outer mold mountingplates, at least one injection unit operatively coupled with one of theouter mold mounting plates and having an injection nozzle, and at leastone reaction injection molding (RIM) device operatively coupled with theother one of the outer mold mounting plates and having a mixing head.

According to another advantageous feature of the invention, the RIMdevice may be implemented as a PUR foaming unit.

According to another advantageous feature of the invention, the centermold carrier element may include two or four opposing mold mountingareas arranged in pairs for affixing two or four corresponding moldhalves, with the center mold carrier element further including a turningdevice capable of closing each of the mold halves of the center moldcarrier element against the mold halves of the outer mold mountingplates.

According to another advantageous feature of the invention, a supportingframe may be fixedly connected to a machine frame for rotatablysupporting the center mold carrier element, wherein the outer moldmounting plates are constructed for slidable support on the machineframe and movement to and away in relation to the center mold carrierelement. When the supporting frame for the center mold carrier elementis attached to the machine frame according to the invention, the centermold carrier element can be supported in a more massive and hence morerobust rotary device, while on the other hand each of the two outer moldmounting plates moves back and forth directly and with a shortdisplacement, i.e., without an intermediate moveable mold mountingplate, relative to the stationary supporting frame of the center moldcarrier element.

According to another advantageous feature of the invention, the centermold carrier element may be plate-shaped and constructed with two moldmounting areas for two center mold halves.

According to another advantageous feature of the invention, the whereinthe center mold carrier element may be constructed in the form of a cubeand provided with four mold mounting areas for four center mold halves.

According to another aspect of the invention, a mold closing device ofan injection molding machine for producing a plastic part made of two ormore plastic components includes two outer mold mounting platessupporting mold halves, a center mold carrier element arranged betweenthe two outer mold mounting plates, a C-shaped supporting framesupporting the turning device and includes an opening that is opentowards a loading/unloading side of the injection molding machine, amachine frame fixedly connected to the supporting frame and displaceablysupporting the outer mold mounting plates.

According to another advantageous feature of the present invention, thesupport plate and the associated outer mold mounting plate may form asandwich plate with an interposed hydraulic pressure piston. This platearrangement has a very short construction and represents a particularlystiff system because the quantity of hydraulic fluid needs to beadequate only for producing the closing pressure. Larger quantities ofhydraulic fluid which can increase the compressibility thereby becomeunnecessary or are only used to operate the actuating drives (closing,loosening and opening), the motion of which is decoupled from thegeneration of the closing pressure. The aforedescribed two-plate closingsystem with an interposed center mold carrying unit, which is fixedlysupported in the machine frame, further enhances the stiffness of themold closing device according to the invention substantially. This moldclosing device can therefore advantageously be used to produce largemulti-component plastic parts which require a highly precise machine,for example automobile glass, interior moldings for automobiles andmulti-wall containers.

According to another advantageous feature of the invention, thesupporting frame which is stationary in the machine frame can have aC-shape, i.e., can be provided with an opening to the loading/unloadingside. In a mold carrier element shaped as a cube and having four moldhalves, the basic component can be injection molded in a first cycle, asreferenced to one of the four mold halves of the mold carrier element.In the second cycle, this component can cool down. In the third cycle,the basic component is finished into a two-component plastic part. Inthe fourth cycle, the mold half with the finished two-component plasticpart is located in the open section of the C-shaped supporting frame andcan be removed during the fourth cycle. Since the removal occurs duringthe fourth cycle, the cycle time can be significantly shortened. Inaddition, inserts, for example metallic threaded sleeves or a plasticpart, can advantageously be placed into the mold half after the finishedtwo-component plastic part has been removed. Alternatively, the C-shapedframe can be operated so that the basic component is located during thesecond cycle on the open side of the frame, making it possible toperform an intermediate processing step during the second cycle whichotherwise would have to be performed during the first cycle. Anexemplary processing step, which typically can occur only after adequatecool-down of the plastic part, can be a surface treatment of the basiccomponent to improve adhesion between the plastic material molded in thefollowing step and the basic component. Such processing step is usefulfor bonding a thermoplastic basic component with a 2-componentThermosetting plastic coating, in particular a polyurethane coating andother like, and can be performed, for example, by a robot located on theside of the mold closing device. In particular, a mold carrier elementwith four or six mold halves shortens the cycle time. The open C-shapedsupporting frame can also be used with a mold carrier element that hasonly two mold halves, since the mold mounting areas can be rotated tothe open section of the supporting frame to allow a mold change or formaintenance work. The particularly short construction of the moldclosing devices of the invention can overcome the more difficult accessto the center mold halves associated with this design.

According to yet another aspect of the present invention, a method ofproducing a plastic part made of two or more plastic components,includes the steps of injection molding a base structure ofthermoplastic material with the aid of an injection unit operativelycoupled to a first outer mold mounting plate, rotating theinjection-molded base structure to face a second outer mold mountingplate, and coating the injection-molded base structure with a coating of2-component thermoset material using a RIM device operatively coupled tothe second outer mold mounting plate.

According to another feature of the present invention, the 2-componentthermoset material may be polyurethane.

According to another feature of the present invention, the coating stepmay involve injection of a PUR reactive mixture and formation of a PURskin on a surface of the base structure.

BRIEF DESCRIPTION OF THE DRAWING

Other features and advantages of the present invention will be morereadily apparent upon reading the following description of currentlypreferred exemplified embodiments of the invention with reference to theaccompanying drawing, in which:

FIG. 1 is a side view on an injection molding machine with a moldclosing device according to the present invention,

FIG. 2 shows a cross-sectional view, on an enlarged scale, of theinjection molding machine, taken along the line II-II in FIG. 1,

FIG. 3 is a side view on another embodiment of a mold closing deviceaccording to the present invention;

FIG. 4 is a side view on an injection molding machine with the moldclosing device of the invention according to the first embodiment with aRIM device,

FIG. 5 shows schematically a top view on the mold closing device of theinvention with an injection nozzle and a mixing head,

FIG. 6 shows schematically a top view on the mold closing device of theinvention with two mixing heads,

FIG. 7 is a side view of an injection molding machine with a C-shapedopen supporting frame disposed fixedly in the machine frame,

FIG. 8 is a cross-sectional view of the injection molding machine ofFIG. 7, taken along the line VIII-VIII of FIG. 7, and

FIG. 9 is a perspective view of the injection molding machine of FIG. 7.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Throughout all the Figures, same or corresponding elements are generallyindicated by same reference numerals. These depicted embodiments are tobe understood as illustrative of the invention and not as limiting inany way. It should also be understood that the drawings are notnecessarily to scale and that the embodiments are sometimes illustratedby graphic symbols, phantom lines, diagrammatic representations andfragmentary views. In certain instances, details which are not necessaryfor an understanding of the present invention or which render otherdetails difficult to perceive may have been omitted.

Turning now to the drawing, and in particular to FIG. 1, there is shownan injection molding machine with a mold closing device 1 and twoinjection units 2 and 3. Arrow 4 indicates schematically the injectionaxis of a third optional injection unit which can be provided on theinjection molding machine in a so-called T-arrangement.

The mold closing unit 1 includes a machine frame 5 on which two outermold mounting plates 6 and 7 are movably supported by slideways 8 and 9.Each of the mold mounting plates 6 and 7 supports a mold half 10 and 11.The mold mounting plate 6 depicted on the left side of FIG. 1 includes aso-called sandwich plate composed of two parallel plates with a smallgap therebetween, wherein one plate is a support plate 6′ and the otherplate is a mold carrier plate 6″. Four hydraulic pressure pistons 12 aredisposed between the support plate 6′ and the mold carrier plate 6″.Only the two front pressure pistons are visible in the drawing.

A center mold carrier element 13 with two opposing mold mounting areas14 and 15 is disposed between the two outer mold mounting plates. A leftand a right center mold half 16 and 17 are each secured to acorresponding mold mounting area 14 and 15. The plate-shaped moldcarrier element 13 depicted in FIG. 1 therefore has two mountingsurfaces 14 and 15. In principle, the mold carrier element can also beshaped as a cube with four mold mounting areas.

The mold carrier element 13 is supported with a vertically orientedrotation axis 18 in a supporting frame 19 that is fixedly connected withthe machine frame 5. A rotary drive 20 disposed of the supporting frame19 can associate the mold carrier element 14 that holds the two centermold halves 16 and 17 with each of the two outer mold halves 10 and 11.

The two outer mold mounting plates 6 and 7 are connected with each otherby four columns 21. The columns 21 are attached to the support plate inthe left outer mold mounting plate 6. The columns 21 penetrate the rightouter mold mounting plate 7 and are locked behind the same. The lockingsystem includes saw tooth-shaped grooves 22 formed in the end region ofthe columns 21, with the complementary saw tooth-shaped grooves of twomutually displaceable half-shells 23 and 24 engaging with the grooves 22like ratchets. The columns 21 penetrate the supporting frame 19 inslideways.

The injection units 2 and 3 are coupled with the outer mold mountingplates 6 and 7 through hydraulic actuating elements 25 and 26 capable ofpositioning the injection nozzles 29 disposed of the mold mountingplates 6 and 7 into an injection position.

The cross-sectional view of FIG. 2 shows the supporting frame 19 securedon the machine frame 5, with the supporting frame 19 penetrated by thecolumns 21. The mold carrier element 13 is rotatably supported in thesupporting frame 19, with the left center mold half 16 secured to themold mounting areas 14 of the mold carrier element 13. The rotation axis18 of the mold carrier element 13 is coupled with the rotary drive 20.Attachment points for hydraulic actuators 27 and 28 (not shown inFIG. 1) are arranged on the outer edge of the supporting frame 19. Thehydraulic actuators 27 and 28 can be used to move the outer moldmounting plates 6 and 7 towards and away from the supporting frame thatis stationary in the machine frame, and can thereby perform the moldclosing motion that brings the mold half 10 of the left outer moldmounting plate 6 into a closing position with the left center mold half16 of the center mold carrier element 13. In the same way andsimultaneously, the mold halves 11 and 17 are brought into a closingposition. The two outer mold mounting plates 6 and 7 are moved towardsthe mold carrier element 16 that is stationary in the machine frame,with the locking system open. The locking system immediately returns toits locking position at the conclusion of the closing motion, with thetwo half-shells 23 and 24 engaging with the saw tooth-shaped grooves 22of the columns 21. The movement into the locking position is indicatedin FIG. 1 by the arrows on the half-shells 23 and 24.

Immediate after the system is locked, the pressure piston 12 producesthe closing pressure, followed by a first injection process via theinjection units 2 and 3 that are docked on the outer mold mountingplates 6 and 7.

After conclusion of the first injection process, the locking system isreleased and the hydraulic actuators 27 and 28 initially loosen theclosed mold halves 10, 12, 16, 17 and subsequently move the outer moldmounting plates 6 and 7 away from the mold carrier element 13 that isstationary in the machine frame, or the supporting frame 19.

The mold carrier element 13 is then rotated by 180°, so that the outermold halves 10 and 11 face the turned-around center mold halves 16 and17. With new pairing of the mold halves, the partially injection moldedparts produced in the first injection molding process are completed in afollowing second injection molding process to produce a finishedtwo-component plastic part.

FIG. 3 shows an embodiment of a mold closing device 30 that is differentfrom the mold closing device 1 depicted in FIG. 1, wherein elementsperforming the same or similar functions are referenced with the samereferenced characters as in FIG. 1.

The mold closing device 30 includes a one-piece outer mold mountingplate 6 having two columns 31 attached thereto. The columns 31 penetrateboth the supporting frame 19 and the right outer mold mounting plate 7,which has four hydraulic cylinders 32, in which cylinders the ends ofthe columns 31 which are formed as pistons 33 are reversibly guided.These piston-cylinder units 32, 33 can be used to perform the travelmotions of the mold closing device 30, such as opening and closing themold halves 10, 11, 16, 17. On the other hand, they can also be used toproduce the closing pressure. A required pressure boosting device isintegrated in the pistons 33 and is not separately shown. Unlike in theembodiment of FIG. 1, the closing pressure is not supported by a lockingsystem, but is maintained hydraulically by the piston-cylinder unit 32,33. Also, unlike the embodiment of FIG. 1, the functions are notseparated. Whereas the closing pressure in the mold closing device 1 ofFIG. 1 is produced by the pressure pistons 12 and the travel motion(opening, closing, loosening) is performed by the hydraulic actuators25, 26, both of these major functions (travel motions and generation ofthe closing pressure) is performed in the mold closing device 30 by thepiston-cylinder unit 32, 33.

Two possible additional applications for a mold closing device 1 areshown in FIGS. 4 to 6, wherein the same elements have the samereferenced characters. FIG. 4 shows the mold closing device 1, with aninjection unit 34 coupled to the support plate 6′ from the left side viaa hydraulic actuator 25. An associated injection nozzle can bepositioned on the mold mounting plate 6 in an injection position. A RIMdevice 35 (RIM: Reaction Injection Molding) is located on the right sideof the mold closing device 1 and is used, for example, for processingpolyurethane (PUR). This device is known in the art and will not bedescribed in detail. It includes essentially feeder and measuringmechanisms for the chemicals to be processed, such as polyol, polyisocyanate and optional additives. The RIM device is coupled to the moldclosing device 1 via a mixing head (not shown in FIG. 4).

FIG. 5 shows schematically a top view of the arrangement of FIG. 4,whereby two possible handling robots 38, 39 are located on either sideof the opened mold halves 10, 16 and 11, 17, respectively. These can bea processing robot 38 and a removal robot 39. The RIM device (which isnot shown in FIG. 5) is coupled via a mixing head 37 to the right moldmounting plate 7, with this mixing head 37 forming aninjection-molding-connection with the right outer mold half 11. With thearrangement depicted in FIG. 4, the basic component is produced asdescribed above. When the molds are open, the surface of the previouslymolded basic component is machined, which can be done by the processingrobot 38. The mold carrier element 13 is then rotated by 180°,whereafter the mold halves are again closed. In the following step, anew basic component is injection-molded on the left side, whereas of theright side the PUR reactive mixture is injected into the mold throughthe mixing head 37, forming a PUR layer on the surface of the basiccomponent. When the molds are subsequently opened, the finishedcomponent can be removed by a removal robot 39 or another removaldevice, while the surface of the basic component can be simultaneouslymachined.

FIG. 6 shows schematically an arrangement similar to that of FIG. 5,with the only difference that the left injection unit 34 with theinjection nozzle 36 is replaced by an additional RIM device (not shown)which is coupled via a mixing head 40 to the left mold mounting plate 6.This arrangement can be used to manufacture by a similar manufacturingprocess multi-component plastic parts, wherein both the basic componentand the coating are made of PUR.

A mold closing device 30 according to FIG. 3 can advantageously be usedto manufacture a multi-component plastic parts that is made at leastpartially of PUR.

Supporting the closing pressure via the locking system according to theembodiment of FIG. 1 provides a particularly stable system that cantolerate a higher stress, so that the mold closing device 1 according toFIG. 1 is particularly suitable for producing high-precision large-sizedmulti-component plastic parts.

Conversely, the embodiment of the mold closing device 30 of FIG. 3 isparticularly suited for economically producing midsize to small sizedmulti-component plastic parts.

The injection molding machine according to FIGS. 7 to 9 includes a moldclosing device 50 and two injection units 51 and 52. The mold closingdevice 50 corresponds essentially to the mold closing device 30 of FIG.3, but uses instead of the closed supporting frame 19 a C-shapedsupporting frame 53 which is open to the loading/unloading side of theinjection molding machine. The C-shaped supporting frame 53 is fixedlyconnected with the machine frame 54 and supports a rotatably supportedmold carrier element 55, on which four center mold halves 56, 57, 58 and59 are clamped. The rotation axis 60 of the mold carrier element 55 issupported in both legs of the C-shaped supporting frame 53 and can bedriven by a rotary drive 61 arranged in the machine frame 54 to performthe aforedescribed cycle. Four columns 62 guided in slideways extendthrough the C-shaped supporting frame 53. The four columns 62 aresecured on one end in a left outer mold mounting plate 63 and extend onthe other end through slideways disposed in a right outer mold mountingplate 64. They are also reversibly guided by pistons 65 moving in fourhydraulic cylinders 65. Both outer mold mounting plates 63 and 64include attachment points 67 and 68 for the injection units 51 and 52,which can be moved by hydraulic actuators 69 and 70 to approach theinjection through-passageways of the mold mounting plates 63 and 64.

The outer mold mounting plates 63 and 64 are slidably supported on themachine frame 54 on side rails 71 and 72. The outer mold mounting plate63 and 64 can therefore be moved by two hydraulic actuators 73 which arelocated on the two diagonally opposed corners of the mold mounting plate64. Only the upper actuator is visible in the FIGS. 7 and 9. The leftouter mold mounting plate 63 is moved by the hydraulic piston-cylinderunit 65, 66.

The four center mold halves 56, 57, 58 and 59 can be closed cyclicallywith the mold halves 74 and 75 arranged on the two outer mold mountingplates 63 and 64.

The injection process will be described hereinafter with reference tothe operating cycle of the center mold half 56. The four cycle positions1 to 4 of the cubic mold carrier element 55, which are offset relativeto each other by 90°, are indicated in FIG. 9 relative to the rotationaxis S. In the first cycle, the two mold halves 56 and 75 are closed anda basic component is injection-molded. In the second cycle, the moldhalf 55 faces the vertical leg of the C-shaped supporting frame 53. Thepreviously injection-molded basic component can then cool down. In thethird cycle, the mold half 56 is closed with the mold half 74 of theleft outer mold mounting plate 63, and the basic component is finishedinto a two-component injection molded part. In the fourth cycle, themold half 56 is rotated into the opening of the C-shaped supportingframe 53. In this position, the finished two-component injection moldedpart can be easily removed and inserts can optionally be placed in theempty mold halves 56. In this operating cycle, the part is removedduring the cycle as determined by the processes closing, closingpressure build-up, injection, after-pressure phase. No additional timeis required for removing the injection molded part. The multi-componentinjection molding machine can be operated with a shortened cycle time,since the part can be simultaneously removed from the open rotated moldhalf.

A mold closing device 50 according to FIG. 7 with a C-shaped frame 53can advantageously also be employed with one or several RIM devices. Inthis case, the mold half with the basic component can be rotated duringthe second cycle into the opening of the C-shaped frame 53, whereby thecomponent first cools down and then receives a surface treatment. In thethird cycle, the mold half with the basic component is closed againstthe mold half that is connected with the mixing nozzle, and thecomponent is finished by applying a PUR coating while a new basiccomponent is injection molded on the other side of the supporting frame.During the next mold opening, the finished component is removed and anew cycle begins. Alternatively, the component can be removed during thefourth cycle, which requires sufficient space between the perpendicularleg of the C-shaped supporting frame 53 and the finished component toallow use of a removal device. Alternatively, the processing step canoccur during the second cycle on the closed side of the C-shapedsupporting frame 53, whereby sufficient space must be provided for theprocessing device, while the completed component is removed on the openside during the fourth cycle.

The mold mounting plates 6, 7 and 62, 63 of the aforedescribed moldclosing devices 1, 30, 50 can be displaced hydraulically orelectromechanically via spindle drives. In principle, a C-shapedsupporting frame 53 that is fixedly secured in the machine frame and hasan opening that is open towards the loading/unloading side, can also beused in the mold closing device 1 where the two mold mounting plates 6and 7 can be moved (opening, closing, loosening) hydraulically orelectromechanically when the locking system (saw tooth-shaped grooves22, half-shells 23, 24) is open and where the closing pressure isproduced via hydraulic pressure pistons 12 in the left mold mountingplate 6 that is formed as a sandwich plate.

While the invention has been illustrated and described in connectionwith currently preferred embodiments shown and described in detail, itis not intended to be limited to the details shown since variousmodifications and structural changes may be made without departing inany way from the spirit of the present invention. The embodiments werechosen and described in order to best explain the principles of theinvention and practical application to thereby enable a person skilledin the art to best utilize the invention and various embodiments withvarious modifications as are suited to the particular use contemplated.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims and includes equivalents of theelements recited therein:

1. A mold closing device for producing a plastic part made of two ormore plastic components, comprising: two outer mold mounting platessupporting mold halves; a center mold carrier element rotatably arrangedbetween the two outer mold mounting plates; at least one injection unitoperatively coupled with one of the outer mold mounting plates andhaving an injection nozzle; and at least one reaction injection molding(RIM) device operatively coupled with the other one of the outer moldmounting plates and having a mixing head.
 2. The mold closing device ofclaim 1, wherein the mixing head is operatively coupled with the moldhalf of the other one of the outer mold mounting plates.
 3. The moldclosing device of claim 1, wherein the RIM device is implemented as aPUR foaming unit.
 4. The mold closing device of claim 1, wherein thecenter mold carrier element includes two or four opposing mold mountingareas arranged in pairs for affixing two or four corresponding moldhalves, the center mold carrier element further including a turningdevice capable of closing each of the mold halves of the center moldcarrier element against the mold halves of the outer mold mountingplates.
 5. The mold closing device of claim 4, further comprising atleast one member selected from the group consisting of injection unitand RIM device, and arranged on the center mold carrier element, whereinthe member is connected for injection with at least one of the moldhalves attached to the center mold carrier element.
 6. The mold closingdevice of claim 1, further comprising a supporting frame fixedlyconnected to a machine frame for rotatably supporting the center moldcarrier element, wherein the outer mold mounting plates are constructedfor slidable support on the machine frame and movement to and away inrelation to the center mold carrier element.
 7. The mold closing deviceof claim 1, wherein the center mold carrier element is plate-shaped andconstructed with two mold mounting areas for two center mold halves. 8.The mold closing device of claim 1, wherein the center mold carrierelement is constructed in the form of a cube and provided with four moldmounting areas for four center mold halves.
 9. A method of producing aplastic part made of two or more plastic components, comprising thesteps of: injection molding a base structure of thermoplastic materialwith the aid of an injection unit operatively coupled to a first outermold mounting plate; rotating the injection-molded base structure toface a second outer mold mounting plate; and coating theinjection-molded base structure with a coating of 2-component thermosetmaterial using a RIM device operatively coupled to the second outer moldmounting plate.
 10. The method of claim 9, wherein the 2-componentthermoset material is polyurethane.
 11. The method of claim 9, andfurther comprising the step of injection molding a further basestructure during the coating step.
 12. The method of claim 9, whereinthe coating step involves injection of a PUR reactive mixture andformation of a PUR skin on a surface of the base structure.
 13. A moldclosing device of an injection molding machine for producing plasticparts made of two or more plastic components, comprising: two outer moldmounting plates supporting mold halves; a center mold carrier elementrotatingly arranged between the two outer mold mounting plates; aC-shaped supporting frame supporting the rotating center mold carrierelement and including an opening that is open towards aloading/unloading side of the injection molding machine; a machine framefixedly connected to the supporting frame and displaceably supportingthe outer mold mounting plates.
 14. The mold closing device of claim 13,wherein the mold carrier element is constructed in the form of a cubeand provided with four mold mounting areas for four center mold halves,and further comprising at least one processing unit for performingprocessing steps on a finished plastic part that is located in the moldhalf facing the opening of the C-shaped supporting frame.
 15. The moldclosing device of claim 13, wherein one of the mold mounting plates isconfigured as a sandwich plate comprising a mold carrier plate and asupport plate in spaced-apart parallel relationship to the mold carrierplate, and further comprising a toggle lever closing system disposedbetween the support plate and the mold carrier plate.
 16. The moldclosing device of claim 13, wherein one of the mold mounting plates isconfigured as a sandwich plate comprising a mold carrier plate and asupport plate in spaced-apart parallel relationship to the mold carrierplate, and further comprising a closing system with a hydraulic pressurepiston disposed between the support plate and the mold carrier plate.17. The mold closing device of claim 13, wherein the C-shaped supportingframe has an upper horizontal leg and a lower horizontal leg, andfurther comprising a vertical leg connecting the horizontal legs. 18.The mold closing device of claim 13, wherein the C-shaped supportingframe has horizontal legs provided with slideways, with at least twocolumns extending through the horizontal legs.
 19. The mold closingdevice of claim 18, wherein one end of each column is fixedly secured onone of the outer mold mounting plates and the other end of the columnincludes a piston, which is reversibly guided in a cylinder unit that isconnected with the outer mold mounting plate, said piston and cylinderunit forming an actuating unit configured to execute an opening andclosing motion of the mold closing device and to produce a closingpressure of the mold closing device.